What a great thread! (pun intended! :-D) I mostly lurk here (love reading all the great tips and information and opinions!), but had to weigh in on this one! I love, love, love my Clover extra fine patchwork pins. I'm a "sew-over" gal, and these pins are so thin that I don't have to worry about going over them with the machine.
Love my OmniGRIP rulers; they don't slide around.
Love a pair of serrated scissors that I have. Their edges grip the fabric, so they are wonderful for applique shapes.
And I should buy stock in Gingher. Like Cat-On-A-Mac, I have duplicates of all my gingher scissors (especially thread-clipping size) -- in my applique take-along basket, beside the ironing board, beside the sewing machine, in the case of the machine I carry to classes, etc. It seems that having multiples ensures I don't lose any!! :-D
Best investment ever? A hand-me-down white, twin-size flannel sheet (my Mom gave it to me so it was FREE!), that I tacked up in my sewing room and use for a Design Wall. Not only do I use it to "design" but also to "store" works in process to stay motivated. My Circuit Rider Quilt applique blocks are on there now to keep me working on my needle-turn applique.
www.cheaperthantherapyquilting.blogspot.com/